<html>
<head><meta charset="utf-8"><title>I-prioritize #79498 Incorrect &quot;unreachable pattern&quot; warning · t-compiler/wg-prioritization/alerts · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/index.html">t-compiler/wg-prioritization/alerts</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html">I-prioritize #79498 Incorrect &quot;unreachable pattern&quot; warning</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="218161993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218161993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218161993">(Nov 28 2020 at 12:21)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="3111">@WG-prioritization/alerts</span> issue <a href="https://github.com/rust-lang/rust/issues/79498">#79498</a> has been requested for prioritization.</p>
<h1><a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#assign-priority-to-unprioritized-issues-with-i-prioritize-label">Procedure</a></h1>
<ul>
<li>Priority?</li>
<li>Regression?</li>
<li>Notify people/groups?</li>
<li>Needs <code>I-nominated</code>?</li>
</ul>



<a name="218163219"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163219" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163219">(Nov 28 2020 at 12:54)</a>:</h4>
<p>Why is this unsound?</p>



<a name="218163225"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163225" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163225">(Nov 28 2020 at 12:55)</a>:</h4>
<p>Is it because you can remove the supposedly unreachable pattern and it will compile?</p>



<a name="218163237"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163237" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163237">(Nov 28 2020 at 12:55)</a>:</h4>
<p>yes: <a href="https://play.rust-lang.org/?version=beta&amp;mode=debug&amp;edition=2018&amp;gist=36e71a8f2d5d7deb36f6c42dcde3c672">https://play.rust-lang.org/?version=beta&amp;mode=debug&amp;edition=2018&amp;gist=36e71a8f2d5d7deb36f6c42dcde3c672</a></p>



<a name="218163285"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163285" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163285">(Nov 28 2020 at 12:56)</a>:</h4>
<p>Right, it’s <a href="https://github.com/rust-lang/rust/issues/79048">#79048</a></p>



<a name="218163287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163287">(Nov 28 2020 at 12:56)</a>:</h4>
<p>I think we should close as duplicate?</p>



<a name="218163351"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163351" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163351">(Nov 28 2020 at 12:58)</a>:</h4>
<p>this is tracking the beta backport I think</p>



<a name="218163353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163353">(Nov 28 2020 at 12:58)</a>:</h4>
<p>because it's p-critical I would not want to be missing a tracking issue for the backport</p>



<a name="218163373"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163373" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163373">(Nov 28 2020 at 12:59)</a>:</h4>
<p>Right, though I think it might make more sense to have <a href="https://github.com/rust-lang/rust/issues/79048">#79048</a> tracking the backport <span aria-label="shrug" class="emoji emoji-1f937" role="img" title="shrug">:shrug:</span></p>



<a name="218163376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163376">(Nov 28 2020 at 12:59)</a>:</h4>
<p>Doesn't really matter anyway</p>



<a name="218163446"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163446" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163446">(Nov 28 2020 at 13:00)</a>:</h4>
<p>If we want to have an issue tracking the backport <code>P-medium</code> seems good</p>



<a name="218163716"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163716" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163716">(Nov 28 2020 at 13:07)</a>:</h4>
<p>I still think this is P-critical, if it lands on stable a <em>lot</em> of the ecosystem will suddenly be unsound</p>



<a name="218163719"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163719" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163719">(Nov 28 2020 at 13:07)</a>:</h4>
<p>ideally it would never have landed on beta</p>



<a name="218163770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163770">(Nov 28 2020 at 13:08)</a>:</h4>
<p>Right, but this is fixed and there is a backport pending</p>



<a name="218163779"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163779" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163779">(Nov 28 2020 at 13:09)</a>:</h4>
<p>that doesn't affect the priority IMO? it's still critical that the backport actually gets applied</p>



<a name="218163780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163780">(Nov 28 2020 at 13:09)</a>:</h4>
<p>IIRC what we have done in the past in those cases is just downgrade the priority to <code>P-medium</code></p>



<a name="218163784"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163784" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163784">(Nov 28 2020 at 13:09)</a>:</h4>
<p>I mean this is already under control</p>



<a name="218163786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163786">(Nov 28 2020 at 13:09)</a>:</h4>
<p>cc <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> , I know you have strong opinions on this <span aria-label="laughing" class="emoji emoji-1f606" role="img" title="laughing">:laughing:</span></p>



<a name="218163789"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163789" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163789">(Nov 28 2020 at 13:09)</a>:</h4>
<p><span class="user-mention silent" data-user-id="255061">Léo Lanteri Thauvin</span> <a href="#narrow/stream/245100-t-compiler.2Fwg-prioritization.2Falerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning/near/218163784">said</a>:</p>
<blockquote>
<p>I mean this is already under control</p>
</blockquote>
<p>right, I understand that, I just think that shouldn't affect the priority</p>



<a name="218163829"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218163829" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218163829">(Nov 28 2020 at 13:10)</a>:</h4>
<p>Well I have to admit I haven't been very active recently, so... x)</p>



<a name="218238719"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238719" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238719">(Nov 30 2020 at 00:35)</a>:</h4>
<p>I think we all agree that the most important thing is to track this :)</p>



<a name="218238737"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238737" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238737">(Nov 30 2020 at 00:36)</a>:</h4>
<p>we've been tagging these kind of things as <code>P-critical</code></p>



<a name="218238781"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238781" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238781">(Nov 30 2020 at 00:37)</a>:</h4>
<p>my opinion differs on what we do but anyway it's not very important, so I'd keep doing what we've been doing, which is tracking these kind of problems with an issue and tag them with <code>P-critical</code></p>



<a name="218238799"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238799" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238799">(Nov 30 2020 at 00:37)</a>:</h4>
<p>my opinion, in case you guys are interested is that the issues should reflect what happens on master and we should be tracking backports through PRs with their corresponding tags</p>



<a name="218238803"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238803" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238803">(Nov 30 2020 at 00:37)</a>:</h4>
<p>I think that's more consistent and enough</p>



<a name="218238867"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2379498%20Incorrect%20%22unreachable%20pattern%22%20warning/near/218238867" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2379498.20Incorrect.20.22unreachable.20pattern.22.20warning.html#218238867">(Nov 30 2020 at 00:38)</a>:</h4>
<p>issues usually reflect the status of master, think for instance about an open issue that is closed in a PR that has a text that says "Closes #XYZ", that may still be an issue on beta/stable and we don't open new issues for those</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>